nbodykit.cosmology.power.transfers

Classes

CLASS(cosmo, redshift) The linear matter transfer function using the CLASS Boltzmann code.
EisensteinHu(cosmo, redshift) The linear matter transfer function using the Eisenstein & Hu (1998) fitting formula with BAO wiggles.
NoWiggleEisensteinHu(cosmo, redshift) Linear power spectrum using the Eisenstein & Hu (1998) fitting formula without BAO wiggles.
class nbodykit.cosmology.power.transfers.CLASS(cosmo, redshift)[source]

The linear matter transfer function using the CLASS Boltzmann code.

Parameters:
  • cosmo (Cosmology) – the cosmology instance
  • redshift (float) – the redshift of the power spectrum

Methods

__call__(k) Return the CLASS linear transfer function at redshift.
__call__(k)[source]

Return the CLASS linear transfer function at redshift. This computes the transfer function from the CLASS linear power spectrum using:

\[T(k) = \left [ P_L(k) / k^n_s \right]^{1/2}.\]

We normalize the transfer function \(T(k)\) to unity as \(k \rightarrow 0\) at \(z=0\).

Parameters:k (float, array_like) – the wavenumbers in units of \(h \mathrm{Mpc}^{-1}\)
Returns:Tk – the transfer function evaluated at k, normalized to unity on large scales
Return type:float, array_like
class nbodykit.cosmology.power.transfers.EisensteinHu(cosmo, redshift)[source]

The linear matter transfer function using the Eisenstein & Hu (1998) fitting formula with BAO wiggles.

Parameters:
  • cosmo (Cosmology) – the cosmology instance
  • redshift (float) – the redshift of the power spectrum

References

Eisenstein & Hu, “Baryonic Features in the Matter Transfer Function”, 1998

Methods

__call__(k) Return the Eisenstein-Hu transfer function with BAO wiggles.
__call__(k)[source]

Return the Eisenstein-Hu transfer function with BAO wiggles.

This is normalized to unity as \(k \rightarrow 0\) at \(z=0\). The redshift scaling is provided by the Cosmology.scale_independent_growth_factor() function.

Parameters:k (float, array_like) – the wavenumbers in units of \(h \mathrm{Mpc}^{-1}\)
Returns:Tk – the transfer function evaluated at k, normalized to unity on large scales
Return type:float, array_like
class nbodykit.cosmology.power.transfers.NoWiggleEisensteinHu(cosmo, redshift)[source]

Linear power spectrum using the Eisenstein & Hu (1998) fitting formula without BAO wiggles.

Parameters:
  • cosmo (Cosmology) – the cosmology instance
  • redshift (float) – the redshift of the power spectrum

References

Eisenstein & Hu, “Baryonic Features in the Matter Transfer Function”, 1998

Methods

__call__(k) Return the Eisenstein-Hu transfer function without BAO wiggles.
__call__(k)[source]

Return the Eisenstein-Hu transfer function without BAO wiggles.

This is normalized to unity as \(k \rightarrow 0\) at \(z=0\). The redshift scaling is provided by the scale_independent_growth_factor() function.

Parameters:k (float, array_like) – the wavenumbers in units of \(h \mathrm{Mpc}^{-1}\)
Returns:Tk – the transfer function evaluated at k, normalized to unity on large scales
Return type:float, array_like